Presuming you are not talking Widow Twankee?? Nobilitation means the act of making one a noble but I prefer QMs word above. less of a mouthful shall we say.
Becoming a dame is the female equivalent of the knighthood.
The honour of knighthood comes from the days of medieval chivalry, as does the method used to confer the knighthood: the accolade, or the touch of a sword by the sovereign.
Although Knights Bachelor do not comprise an order of chivalry, knighthood is a dignity which has its origins in Britain in Saxon times. They are styled "Sir" (except for clergymen who do not receive the accolade) and their wives "Lady".
Women receiving the honour are styled "dame" but do not receive the accolade. Instead their honour is pinned on them - in order, say officials, to avoid a sword "disaster" caused by their hats. (??!!)
Investitures are held twice a year at Buckingham Palace and they alternate between the Queen and Prince Phillip. Once invested, a Dame can not only be addressed using the title - her mail can be sent to Dame (So and So) DBE.